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Resolution of racemic Amphetamine

Two mols, for example, 270 grams, of racemic amphetamine base are reacted with one mol (150 grams) of d-tartaric acid, thereby forming dl-amphetamine d-tartrate, a neutral salt. The neutral salt thus obtained is fully dissolved by the addition of sufficient, say about 1 liter, of absolute ethanol, and heating to about the boiling point. The solution is then allowed to cool to room temperature with occasional stirring to effect crystallization. The crystals are filtered off and will be found to contain a preponderance of the levo enantiomorph.

The residual solid in the mother liquors is repeatedly and systematically crystallized, yielding a further fraction of amphetamine d-tartrate which may be purified by recrystallization. d-amphetamine may be readily recovered from the mother liquors by the addition of tartaric acid thereto for the formation of acid tartrates and separation of d-amphetamine d-bitartrate by crystallization.

The free base of either optical isomer may be obtained by addition to the d-tartrate in the case of the levo isomer and the d-bitartrate in the case of the dextro isomer of alkali in excess, as, for example, by the addition of an aqueous solution of caustic soda, which will cause the base to separate as an oil which may be recovered and purified by any well-known procedure. The base is exactly neutralized with sulfuric acid to give the sulfate.

References

Merck Index 2918 PDR pp. 1450, 1711
OCDS Vol. 1 p.70 (1977)
I.N. p. 301
REM p.881
Nabenhauer, F.P.; U.S. Patent 2,276,508; March 17, 1942.

Forfatter:	Endorfiner [ 16 mar 2015 14:09 ]
Titel:	adskillelse af amfetamin isomer
ville høre om en kemi-kyndig person kan be- eller afkræfte dette? har fornyligt set et write-up på seperation af amfetamins isomer og det jo mildest talt en meget kompliceret process, så ville være interessant hvis nedestående er legitimt. Og i så fald vil det ikke være et bedre opløsningsmiddel end ethanol til formålet? Citat: Resolution of racemic Amphetamine Two mols, for example, 270 grams, of racemic amphetamine base are reacted with one mol (150 grams) of d-tartaric acid, thereby forming dl-amphetamine d-tartrate, a neutral salt. The neutral salt thus obtained is fully dissolved by the addition of sufficient, say about 1 liter, of absolute ethanol, and heating to about the boiling point. The solution is then allowed to cool to room temperature with occasional stirring to effect crystallization. The crystals are filtered off and will be found to contain a preponderance of the levo enantiomorph. The residual solid in the mother liquors is repeatedly and systematically crystallized, yielding a further fraction of amphetamine d-tartrate which may be purified by recrystallization. d-amphetamine may be readily recovered from the mother liquors by the addition of tartaric acid thereto for the formation of acid tartrates and separation of d-amphetamine d-bitartrate by crystallization. The free base of either optical isomer may be obtained by addition to the d-tartrate in the case of the levo isomer and the d-bitartrate in the case of the dextro isomer of alkali in excess, as, for example, by the addition of an aqueous solution of caustic soda, which will cause the base to separate as an oil which may be recovered and purified by any well-known procedure. The base is exactly neutralized with sulfuric acid to give the sulfate. References Merck Index 2918 PDR pp. 1450, 1711 OCDS Vol. 1 p.70 (1977) I.N. p. 301 REM p.881 Nabenhauer, F.P.; U.S. Patent 2,276,508; March 17, 1942.

Forfatter:	smiley-g [ 17 mar 2015 19:53 ]
Titel:	Re: adskillelse af amfetamin isomer
nu kan det godt være jeg spørger lidt dumt: men er det ikke MEGET nemmere at lave en søjlechromatografi? kan det overhovedet lade sig gøre at adskille isomere på den måde?

Forfatter:	Imp [ 17 mar 2015 21:31 ]
Titel:	Re: adskillelse af amfetamin isomer
Det ser nu meget legit ud. Det er en standard metode til at skille enantiomere fra hinanden og tartaric acid (vinsyre) er ret billigt. Men du skal nok helst have meget rent amfetamin til at starte med. Ellers løber man nok hurtigt ind i problemer. smiley-g skrev: nu kan det godt være jeg spørger lidt dumt: men er det ikke MEGET nemmere at lave en søjlechromatografi? kan det overhovedet lade sig gøre at adskille isomere på den måde? Man kan ikke normalt skille enantiomerer ad ved søjlekromatografi. Kun hvis du har en kiral stationær fase, som vil interagere forskelligt med de to enantiomerer. Men det er som udgangspunkt en meget dyr metode og kan ikke betale sig på preparativ skala, medmindre det er i industrien eller lignende. Nogle gange studser jeg over skalaen, da man lavede kemi i gamle dage. Citat: Two mols, for example, 270 grams, of racemic amphetamine base are reacted... Det var alligevel ikke så lidt bare for at lave et eksempel

Forfatter:	Endorfiner [ 20 mar 2015 12:41 ]
Titel:	Re: adskillelse af amfetamin isomer
Imp skrev: Det ser nu meget legit ud. Det er en standard metode til at skille enantiomere fra hinanden og tartaric acid (vinsyre) er ret billigt. Men du skal nok helst have meget rent amfetamin til at starte med. Ellers løber man nok hurtigt ind i problemer. Super! Tak for svaret Kan se den gængse vinsyre er levotartaric acid. Er det en nem metode til at opnå dextro på? eller er jeg påtvunget til at købe til vanvittig pris hos biolabs? Skal bruge begge sådan som jeg har forstået det. Imp skrev: Nogle gange studser jeg over skalaen, da man lavede kemi i gamle dage. Det var alligevel ikke så lidt bare for at lave et eksempel

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